The present invention relates to an automotive air-conditioning apparatus, and more particularly to an automotive air-conditioning apparatus for heating an electric power motor with exciting electric power as a heating or warming source.
Conventionally, a combustion type heater has been extensively used for heating the air in a passenger compartment or as a heat source for heating in vehicles. On the other hand, although electric vehicles and hybrid vehicles have been developed recently as countermeasures to environmental pollution, combustion type heaters have conventionally been used as a heat source for heating in such low environmental pollution vehicles.
However, the combustion type heater suffers in that it pollutes the environment by the generation of a combustion exhaust gas. Thus, this heat source for heating runs counter to the intended purpose of a low environmental pollution vehicle. Consequently, it is necessary to develop a non-combustion type heater as heater for heating that meets the intended purpose of electric and hybrid vehicles, i.e. low environmental pollution.
In view of the foregoing problems inherent in the prior art, an object of the present invention is to provide an automotive air-conditioning apparatus which meets the intended purpose of low environmental pollution vehicles such as electric and hybrid vehicles, and which may perform high quality heating with low environmental pollution.
In order to attain these and other objects, according to one aspect of the present invention, there is provided an automotive air-conditioning apparatus comprising a hot water circuit for heating a passenger compartment, the hot water circuit including a hot water heater, a hot water circulating pump, and a heater core for heating the air of the passenger compartment using hot water conveyed by the hot water circulating pump, wherein: the hot water heater comprises at least one electric motor as a heat source, the electric motor being electromagnetically excited in a state such that the rotation thereof is restricted to thereby generate heat.
With such an arrangement, since the heat generated in the electric motor by the exciting power is used as the heat source for heating passenger compartment air, it is possible to perform heating operations with the non-combustion type heater. Accordingly, it is possible to provide an automotive air-conditioning apparatus with no potential for polluting the air and that meets the object of low environmental pollution. Further, it is possible to consider an electric heater for heating air, such as a sheathed type heater using a resistor wire as a heating element, as a heat source using electric power. However, the temperature of the resistor wire is high, and there is a fear that a fire might be generated or the wire might break. Accordingly, this is not particularly suitable for use in a vehicle which is subjected to frequent vibrations. In contrast, in the case where an electric motor is used to generate heat as in the present invention, the heating area of the heating wire is made so large that the temperature of the exciting winding may be suppressed to a relatively low level. Thus, such a disadvantage may be overcome.
Also, the restricting means may be easily attained according to a second aspect of the invention, by connecting two motors which are electromagnetically excited in reverse rotational directions to each other or alternatively, according to a third aspect of the invention by using a lock mechanism.
Also, according to a fourth aspect of the invention, the automotive air-conditioning apparatus further comprises a refrigerant circuit for cooling the passenger compartment, the refrigerant circuit comprising a compressor, an exterior heat exchanger, an expansion mechanism, and an interior heat exchanger, wherein: the compressor is driven by the electric motor while the rotation of the electric motor is in a non-restricted state. With such an arrangement, the cooling operation, as well as the above-described heating operation, may be performed by using the electric motor per se for generating heat by the exciting power and also for driving the compressor, so the cost therefor may be reduced.
Also according to a fifth aspect of the invention, the automotive air-conditioning apparatus further comprises a refrigerant circuit for cooling the passenger compartment, the refrigerant circuit comprising a compressor, an exterior heat exchanger, an expansion mechanism, and an interior heat exchanger, wherein: the two electric motors comprise a reversible-rotation motor capable of rotating in a reversible rotational direction, and a constant-rotation motor having a rotational torque that is greater than that of the reversible-rotation motor, and by selectively switching the electromagnetic exciting direction of the reversible-rotation motor the two electric motors are driven in the same rotational direction or reverse rotational direction to each other, with the result that the compressor is driven by the constant-rotation motor that is electromagnetically excited.
With such an arrangement, the two electric motors are excited to be rotated in the same constant rotational direction so that the cooling operation may be performed by the refrigerant circuit. Also, the reversible-rotation motor having the smaller rotational torque is excited to be rotated in the reverse rotational direction so that the two electric motors are excited in the reverse rotational directions to each other, and the rotations thereof are restricted to generate the heat. However, the compressor is rotated by the constant-rotation motor having the larger rotational torque. Accordingly, the heating operation by the hot water circuit using the heat generated by the two electric motors as the heat source and the cooling operation for cooling the passenger compartment air through the refrigerant circuit are simultaneously performed to perform a so-called dehumidifying operation.
Also, in a sixth aspect of the invention, there is provided an automotive air-conditioning apparatus, comprising: a hot water circuit for heating a passenger compartment comprising a hot water heater, a hot water circulating pump, and a heater core for heating the air of the passenger compartment using hot water conveyed by the hot water circulating pump, and a refrigerant circuit for cooling the passenger compartment comprising a compressor connected to a first electric motor, an exterior heat exchanger, an expansion mechanism, and an interior heat exchanger, wherein: the hot water heater comprises at least a second electric motor and a heater utilizing fluid frictional heat as a heat source, the second electric motor generating heat by being electromagnetically excited in a state such that the rotation thereof is restricted by a lock mechanism, the heater utilizing fluid frictional heat comprising two rotors that are located adjacent to and facing each other and viscous fluid interposed between the two rotors, the two rotors being respectively fixed to each of the drive shafts of the first and second electric motors so as to integrally rotate therewith, thereby, the heater utilizing fluid frictional heat being constructed so as to generate fluid frictional heat in the viscous fluid when the second electric motor is restricted and the first electric motor is rotated, the first electric motor being connected to second electric motor through the heater utilizing fluid frictional heat.
With such an arrangement, without locking the second electric motor provided with the lock mechanism, both the first and second electric motors are excited in the same rotational direction to drive the compressor to thereby perform the cooling operation through the refrigerant circuit. Also, the second electric motor is locked by said lock mechanism and the first and second electric motors are exited in the same rotational direction to drive the compressor so that the heating operation through the hot water circuit using the heat generated by the heater utilizing fluid frictional heat and the heat generated by the exciting power of the second electric motor as the heat source is performed, and the above-described cooling operation through the refrigerant circuit is simultaneously performed. As a result, a dehumidifying operation having a large heating performance, i.e., a dehumidifying operation with a touch of heating may be performed. Also, in this condition, when the excitation of the first electric motor is turned off, the heat generation effect of the heater utilizing fluid frictional heat is stopped. Accordingly, the heating capacity is reduced. However, since the cooling operation by the refrigerant circuit is stopped, it is possible to perform the heating operation. Also, when in the condition of the dehumidifying operation with a touch of heating the excitation of the second electric motor is turned off, the heat generating effect of the second electric motor is stopped. As a result, the heating capacity becomes small. The dehumidifying operation having the small heating capacity, i.e., a dehumidifying operation with a touch of cooling may be performed. As described above, according to this aspect of the present invention, four operating modes may be performed.
Also, according to the seventh to ninth aspects of the present invention, the refrigerant circuit in the fourth to sixth aspects of the present invention, is a reversible cycle type, that may be controlled to be selectively switched over reversibly.
Accordingly, according to the seventh aspect of the present invention, when the refrigerant circuit is switched over to the heating cycle to drive the compressor, a heating operation through the refrigerant circuit switched into the heating cycle is performed, and a heat pump type heating operation may be performed to suck in the heat from the outside air.
Also, according to the eighth aspect of the present invention, when the refrigerant circuit is switched over to the heating cycle and the two electric motors are excited in the same rotational direction to drive the compressor, a heating operation is performed by the refrigerant circuit which serves as the heating cycle so that a heat pump type heating operation can be performed. Also, according to the eighth aspect of the present invention, when the refrigerant circuit is switched over to the heating cycle and the two electric motors are excited in rotational directions reverse to each other to drive the compressor, a heating operation through the hot water circuit using the heat generated by the electric motor as a heat source and a heating operation through the refrigerant circuit that serves as the heating cycle are simultaneously performed so that a heating operation having a large heating capacity may be performed. Accordingly, in addition to the two operational modes according to the fifth aspect of the present invention, the two additional heating operational modes may also be provided.
Also, according to a ninth aspect of the present invention, when the refrigerant circuit in the sixth aspect of the present invention is switched over to the heating cycle the second electric motor is not locked and the first electric motor is excited to drive the compressor, a heating operation through the refrigerant circuit which serves as the heating cycle is performed and a heat pump type heating operation can be performed. Also, according to the ninth aspect to the present invention, when the refrigerant circuit is switched over to the heating cycle and the second electric motor is locked by means of the lock mechanism to excite the two electric motors, the compressor is driven and the second electric motor operates to generate heat by the excitation power. Furthermore, the heater utilizing fluid frictional heat operates to generate heat. Accordingly, the heating operation through the hot water circuit using the heat generated by the heater utilizing fluid frictional heat and the heat generated by the excitation power of the second electric motor as the heat source and the heating operation through the refrigerant circuit which serves as the heating cycle are simultaneously performed. Accordingly, a heating operation having a large heating capacity using the three heat sources may be performed. Also, when the excitation of the second electric motor is stopped under this condition the second electric motor does not generate heat, and a heating operation having a correspondingly reduced heating capacity may be performed. Thus, it is possible to add the above described three heating operational modes to the four operational modes according to the sixth aspect of the present invention.